Separation for the stationary Prandtl equation
|
|
- Garry Greene
- 5 years ago
- Views:
Transcription
1 Separation for the stationary Prandtl equation Anne-Laure Dalibard (UPMC) with Nader Masmoudi (Courant Institute, NYU) February 13th-17th, 217 Dynamics of Small Scales in Fluids ICERM, Brown University
2 Outline Introduction Behaviour near separation: heuristics and formal results Main result and ideas Conclusion and perspectives
3 Introduction Plan Introduction Behaviour near separation: heuristics and formal results Main result and ideas Conclusion and perspectives
4 Introduction What is boundary layer separation? Flow with low viscosity around an obstacle, in the presence of an adverse pressure gradient (=the outer flow is decreasing along the obstacle): Figure: Cross-section of a flow past a cylinder (source: ONERA, France) After separation: widely open problem (turbulence?) Mathematical interest: understand the vanishing viscosity limit in the Navier-Stokes equation. Industrial interest: reduce drag.
5 Introduction Derivation of the (stationary) Prandtl system Starting point: stationary 2d Navier-Stokes with small viscosity ν 1 in a half-plane. Velocity field u ν : R 2 + R 2 with Ansatz: u ν (x, y) (u ν )u ν + p ν ν u ν = f in R 2 +, divu ν = in R 2 +, u ν y= =. (1) { u E (x, y) for y ( ( ) ν (sol. of 2d Euler), y u x, ν, ( )) y νv x, ν for y ν. Stationary Prandtl system: with Y = y/ ν, u x u + v Y u YY u = f 1 (x, ) pe (x, ) x x u + Y v =, u Y = =, v Y = =, lim Y u = ue (x, ).
6 Introduction Derivation of the (stationary) Prandtl system Starting point: stationary 2d Navier-Stokes with small viscosity ν 1 in a half-plane. Velocity field u ν : R 2 + R 2 with Ansatz: u ν (x, y) (u ν )u ν + p ν ν u ν = f in R 2 +, divu ν = in R 2 +, u ν y= =. (1) { u E (x, y) for y ( ( ) ν (sol. of 2d Euler), y u x, ν, ( )) y νv x, ν for y ν. Stationary Prandtl system: with Y = y/ ν, u x u + v Y u YY u = f 1 (x, ) pe (x, ) x x u + Y v =, u Y = =, v Y = =, lim Y u = ue (x, ).
7 Introduction Derivation of the (stationary) Prandtl system Starting point: stationary 2d Navier-Stokes with small viscosity ν 1 in a half-plane. Velocity field u ν : R 2 + R 2 with Ansatz: u ν (x, y) (u ν )u ν + p ν ν u ν = f in R 2 +, divu ν = in R 2 +, u ν y= =. (1) { u E (x, y) for y ( ( ) ν (sol. of 2d Euler), y u x, ν, ( )) y νv x, ν for y ν. Stationary Prandtl system: with Y = y/ ν, u x u + v Y u YY u = f 1 (x, ) pe (x, ) x x u + Y v =, u Y = =, v Y = =, lim Y u = ue (x, ).
8 Introduction The stationary Prandtl equation: general existence result Stationary Prandtl system: u x u + v Y u YY u = g(x) x u + Y v =, u x= = u u Y = =, v Y = =, lim Y u = ue (x, ). (P) Nonlocal, scalar evolution eq. in x. Locally well-posed as long as u > : Theorem [Oleinik, 1962]: Let u C 2,α b (R + ), α >. Assume that u (Y ) > for Y >, u () >, and that YY u + g() = O(Y 2 ) for < Y 1. Then there exists x > such that (P) has a unique strong C 2 solution in {(x, Y ) R 2, x < x, Y }. If g(x), then x = +.
9 Introduction The stationary Prandtl equation: general existence result Stationary Prandtl system: u x u + v Y u YY u = g(x) x u + Y v =, u x= = u u Y = =, v Y = =, lim Y u = ue (x, ). (P) Nonlocal, scalar evolution eq. in x. Locally well-posed as long as u > : Theorem [Oleinik, 1962]: Let u C 2,α b (R + ), α >. Assume that u (Y ) > for Y >, u () >, and that YY u + g() = O(Y 2 ) for < Y 1. Then there exists x > such that (P) has a unique strong C 2 solution in {(x, Y ) R 2, x < x, Y }. If g(x), then x = +.
10 Introduction The stationary Prandtl equation: monotonicity, comparison principle Nonlinear change of variables [von Mises]: transforms (P) into a local diffusion equation (porous medium type). Maximum principle holds for the new eq. by standard tools and arguments. Monotonicity is preserved by (P). Comparison principle for the Prandtl equation: Consider a super-solution ū for Prandtl; Von Mises sub/super solution w for the eq. in new variables; Maximum principle for the new eq.: w w. ODE arguments: u ū. Remark: we will consider strictly increasing solutions only: ensures that separation happens at the boundary.
11 Introduction General mechanism behind separation Setting: monotone solutions with adverse pressure gradient (g ). In general there exists x such that u =. Y x=x,y = For x > x, Y. 1, u takes negative values: reversed flow near the boundary. There exists a curve Y = F (x) such that u(x, F (x)) = : separation of the boundary layer. Definition: x is called the separation point.
12 Introduction Questions 1. Does separation really happen? Can you cook-up solutions of (P) such that Y u Y = (x) as x x for some finite x? 2. If you can, what is the rate at which Y u Y = (x) vanishes?
13 Introduction Related results Instability results (time dependent version): Local well-posedness in high regularity spaces (analytic, Gevrey) [Sammartino& Caflisch; Gérard-Varet& Masmoudi...] or for monotonic data [Oleinik; Masmoudi&Wong; Alexandre, Wang, Xu& Yang...] BUT instabilities develop in short time in Sobolev spaces [Grenier; Gérard-Varet&Dormy...] Formation of singularities (time dependent version): [Kukavica, Vicol, Wang](van Dommelen-Shen singularity) Starting from real analytic initial data, for specific outer Euler flow, some solutions display singularities in finite time. Justification of the Prandtl Ansatz when ν 1: [Guo& Nguyen, Iyer] Starting from stationary Navier-Stokes above a moving plate (non-zero boundary condition on the wall), local convergence/global convergence for small data ( no singularity).
14 Behaviour near separation: heuristics and formal results Plan Introduction Behaviour near separation: heuristics and formal results Main result and ideas Conclusion and perspectives
15 Behaviour near separation: heuristics and formal results Formal derivations of the self similar rate Formal computations of an exact solution to (P) by [Goldstein 48, Stewartson 58] thanks to Taylor expansions in self-similar variables. Self similar change of variables: rely on the observation that (P) is invariant by the scaling u(x, Y ) 1 µ u(µx, µ 1/4 Y ), v(x, y) µ 1/4 v(µx, µ 1/4 Y ), with µ >. Remark: the coefficients of the asymptotic expansion are never entirely determined (dependence on initial data?) Heuristic argument by Landau: Y u Y = (x) x x. (same as Goldstein& Stewartson.)
16 Behaviour near separation: heuristics and formal results Statement by Luis Caffarelli and Weinan E In a paper published in 2, Weinan E announces a joint result with Luis Caffarelli, stating: Theorem [Caffarelli, E, 1995]: Assume that g(x) = 1, and that u satisfies u 2 3 Y 2 Y u u. Then: There exists x > such that the solution cannot be extended beyond x ; The family u µ := 1 µ u(µ(x x), µ 1/4 Y ) is compact in C(R 2 +). The author also states two (non-trivial...) Lemmas playing a key role in the proof, relying on the maximum principle. Unfortunately the complete proof was never published... Goal of the present talk: propose an alternate proof, relying on different techniques, and giving a more quantitative result.
17 Behaviour near separation: heuristics and formal results Statement by Luis Caffarelli and Weinan E In a paper published in 2, Weinan E announces a joint result with Luis Caffarelli, stating: Theorem [Caffarelli, E, 1995]: Assume that g(x) = 1, and that u satisfies u 2 3 Y 2 Y u u. Then: There exists x > such that the solution cannot be extended beyond x ; The family u µ := 1 µ u(µ(x x), µ 1/4 Y ) is compact in C(R 2 +). The author also states two (non-trivial...) Lemmas playing a key role in the proof, relying on the maximum principle. Unfortunately the complete proof was never published... Goal of the present talk: propose an alternate proof, relying on different techniques, and giving a more quantitative result.
18 Main result and ideas Plan Introduction Behaviour near separation: heuristics and formal results Main result and ideas Conclusion and perspectives
19 Main result and ideas Main result Theorem [D., Masmoudi, 16]: Consider the equation (P) with g(x) = 1. Then for a class of initial data u = u x= satisfying u is strictly increasing with respect to Y ; u (Y ) λ Y + Y 2 2 for Y 1 and for some λ 1; separation occurs at a finite distance x = O(λ 2 ). Moreover for all x (, x ), λ(x) := Y u Y = (x) C x x and for some weight w = w(x, Y ), u u app L 2 (w) = o( u app L 2 (w)) as x x, where for Y (x x) 1/4 u app (x, Y ) = λ(x)y + Y 2 2 αy 4 βλ(x) 1 Y 7.
20 Main result and ideas Main result Theorem [D., Masmoudi, 16]: Consider the equation (P) with g(x) = 1. Then for a class of initial data u = u x= satisfying u is strictly increasing with respect to Y ; u (Y ) λ Y + Y 2 2 for Y 1 and for some λ 1; separation occurs at a finite distance x = O(λ 2 ). Moreover for all x (, x ), λ(x) := Y u Y = (x) C x x and for some weight w = w(x, Y ), u u app L 2 (w) = o( u app L 2 (w)) as x x, where for Y (x x) 1/4 u app (x, Y ) = λ(x)y + Y 2 2 αy 4 βλ(x) 1 Y 7.
21 Main result and ideas Remarks Two results: asymptotic behavior of Y u Y = and error estimate between u and u app. The self-similar rate is the one predicted by Landau, Goldstein and Stewartson. Existence of other (unstable) rates? Comparison with result by Caffarelli and E: Encompasses their result; More stringent assumptions; Quantitative result; the limit is identified. Tools and scheme of proof: Inspired by study of blow-up rates for NLS [Zakharov, Sulem& Sulem; Merle& Raphaël]; successfully applied to wave and Schrödinger maps, Keller-Segel system, harmonic heat flow [Merle, Raphaël, Rodnianski, Schweyer...] Perform a self-similar change of variables; approximate solution, energy estimates in rescaled variables; Use techniques based on modulation of variables to find the self-similar rate λ(x) = Y u Y =.
22 Main result and ideas Remarks Two results: asymptotic behavior of Y u Y = and error estimate between u and u app. The self-similar rate is the one predicted by Landau, Goldstein and Stewartson. Existence of other (unstable) rates? Comparison with result by Caffarelli and E: Encompasses their result; More stringent assumptions; Quantitative result; the limit is identified. Tools and scheme of proof: Inspired by study of blow-up rates for NLS [Zakharov, Sulem& Sulem; Merle& Raphaël]; successfully applied to wave and Schrödinger maps, Keller-Segel system, harmonic heat flow [Merle, Raphaël, Rodnianski, Schweyer...] Perform a self-similar change of variables; approximate solution, energy estimates in rescaled variables; Use techniques based on modulation of variables to find the self-similar rate λ(x) = Y u Y =.
23 Main result and ideas Remarks Two results: asymptotic behavior of Y u Y = and error estimate between u and u app. The self-similar rate is the one predicted by Landau, Goldstein and Stewartson. Existence of other (unstable) rates? Comparison with result by Caffarelli and E: Encompasses their result; More stringent assumptions; Quantitative result; the limit is identified. Tools and scheme of proof: Inspired by study of blow-up rates for NLS [Zakharov, Sulem& Sulem; Merle& Raphaël]; successfully applied to wave and Schrödinger maps, Keller-Segel system, harmonic heat flow [Merle, Raphaël, Rodnianski, Schweyer...] Perform a self-similar change of variables; approximate solution, energy estimates in rescaled variables; Use techniques based on modulation of variables to find the self-similar rate λ(x) = Y u Y =.
24 Main result and ideas The self-similar change of variables Let λ(x) := Y u Y = (x). Define ũ = ũ(x, ξ) by Then λ 4 ( ũũ x ũ ξ ξ Define s, b, U such that b = 2λ x λ 3, Then U satisfies ũ(x, ξ) = λ 2 (x)u(x, λ(x)ξ). ũ x ) + λ x λ 3 ( 2ũ 2 3ũ ξ ξ dx ds = λ4, ξ UU s U ξ U s bu 2 + 3b 2 U ξ ) ũ ũ ξξ = 1. U(s, ξ) = ũ(x(s), ξ). ξ U U ξξ = 1. Remark: x x corresponds to s provided x λ 4 =. (R)
25 Main result and ideas The self-similar change of variables Let λ(x) := Y u Y = (x). Define ũ = ũ(x, ξ) by Then λ 4 ( ũũ x ũ ξ ξ Define s, b, U such that b = 2λ x λ 3, Then U satisfies ũ(x, ξ) = λ 2 (x)u(x, λ(x)ξ). ũ x ) + λ x λ 3 ( 2ũ 2 3ũ ξ ξ dx ds = λ4, ξ UU s U ξ U s bu 2 + 3b 2 U ξ ) ũ ũ ξξ = 1. U(s, ξ) = ũ(x(s), ξ). ξ U U ξξ = 1. Remark: x x corresponds to s provided x λ 4 =. (R)
26 Main result and ideas The self-similar change of variables Let λ(x) := Y u Y = (x). Define ũ = ũ(x, ξ) by Then λ 4 ( ũũ x ũ ξ ξ Define s, b, U such that b = 2λ x λ 3, Then U satisfies ũ(x, ξ) = λ 2 (x)u(x, λ(x)ξ). ũ x ) + λ x λ 3 ( 2ũ 2 3ũ ξ ξ dx ds = λ4, ξ UU s U ξ U s bu 2 + 3b 2 U ξ ) ũ ũ ξξ = 1. U(s, ξ) = ũ(x(s), ξ). ξ U U ξξ = 1. Remark: x x corresponds to s provided x λ 4 =. (R)
27 Main result and ideas Strategy From now on, work only on equation on U: ξ UU s U ξ U s bu 2 + 3b 2 U ξ ξ U U ξξ = 1. At this stage, b is an unknown. The asymptotic behavior of b dictates the self-similar rate λ(x). Scheme of proof: 1. Construct an approximate solution; 2. Choose the approximate solution with the least possible growth at infinity: heuristics for the modulation rate b; 3. Energy estimate on the remainder of the solution. Rule of thumb: the expected rate λ(x) = C x x corresponds to b(s) = 1 s b s + b 2 =.
28 Plan Introduction Behaviour near separation: heuristics and formal results Main result and ideas Conclusion and perspectives
29 Plan Introduction Behaviour near separation: heuristics and formal results Main result and ideas The approximate solution Energy estimates Conclusion and perspectives
30 Construction of an approximate solution ξ ξ UU s U ξ U s bu 2 + 3b 2 U ξ U U ξξ = 1. }{{} =:A(U) Boundary conditions at ξ = : by definition of λ, U ξ= =, ξ U ξ= = 1. Case b = : exact stationary solution U := ξ + ξ2 2 ( ground state ). Case b : Look for asymptotic expansion in the form U = U + bt 1 + b 2 T 2 + Then T 1 is given by b ξξ T 1 = A(U ) + 1 T 1 = ξ4 48. What about T 2?
31 Finding the ODE on b Rule: choice of the approx. solution with the least possible growth. Remainder for U 1 := U + bt 1 : A(U 1 ) ξξ U ( 4 = α 5 b s + 13 ) 1 b2 ξ α ( b s + b 2) ξ 6 + α 2 b ( bs + b 2) ξ 8. 5 Choice of b such that the ξ 6 term disappears: b s + b 2 =. Ansatz: in the algorithm defining T N, replace every occurrence of b s by b 2. Consequence: setting U N := U + bt b N T N, U U 2 (b s + b 2 )(c 7 ξ 7 + c 8 ξ 8 ) near ξ =. U U N b s + b 2 for N 2.
32 Finding the ODE on b Rule: choice of the approx. solution with the least possible growth. Remainder for U 1 := U + bt 1 : A(U 1 ) ξξ U ( 4 = α 5 b s + 13 ) 1 b2 ξ α ( b s + b 2) ξ 6 + α 2 b ( bs + b 2) ξ 8. 5 Choice of b such that the ξ 6 term disappears: b s + b 2 =. Ansatz: in the algorithm defining T N, replace every occurrence of b s by b 2. Consequence: setting U N := U + bt b N T N, U U 2 (b s + b 2 )(c 7 ξ 7 + c 8 ξ 8 ) near ξ =. U U N b s + b 2 for N 2.
33 Finding the ODE on b Rule: choice of the approx. solution with the least possible growth. Remainder for U 1 := U + bt 1 : A(U 1 ) ξξ U ( 4 = α 5 b s + 13 ) 1 b2 ξ α ( b s + b 2) ξ 6 + α 2 b ( bs + b 2) ξ 8. 5 Choice of b such that the ξ 6 term disappears: b s + b 2 =. Ansatz: in the algorithm defining T N, replace every occurrence of b s by b 2. Consequence: setting U N := U + bt b N T N, U U 2 (b s + b 2 )(c 7 ξ 7 + c 8 ξ 8 ) near ξ =. U U N b s + b 2 for N 2.
34 Plan Introduction Behaviour near separation: heuristics and formal results Main result and ideas The approximate solution Energy estimates Conclusion and perspectives
35 Obtaining stability estimates General idea: control (b s + b 2 ) 2 via an appropriate energy E(s) := U U N 2. Goal: prove that E(s) = O(s 4 η ) for some η >. (2) Starting point: write eq. on U U N for N large (N = 3). of the form s (U U N ) + = remainder terms. Error estimate: prove that de ds + α E(s) ρ(s). s In order to achieve (2), one needs: ρ(s) = O(s 5 η ): good approximate solution; α > 4: algebraic manipulations on the equation (R).
36 A transport-diffusion equation for U Define, for W L (R + ), ξ L U W := UW U ξ W = so that, if W (ξ) = O(ξ 2 ) near ξ =, L 1 U W = (U ξ ( ξ W ) U 2, U ξ ) W U 2. ξ Remark: L 1 U division by U ξ + ξ2 /2. Then (R) can be written as s U bu + b 2 ξ ξu L 1 U ( ξξu 1) =. Define L U := L 1 U ξξ: diffusion operator. Then, with V = U U N s V bv + b 2 ξ ξv L U V = R N.
37 A transport-diffusion equation for U Define, for W L (R + ), ξ L U W := UW U ξ W = so that, if W (ξ) = O(ξ 2 ) near ξ =, L 1 U W = (U ξ ( ξ W ) U 2, U ξ ) W U 2. ξ Remark: L 1 U division by U ξ + ξ2 /2. Then (R) can be written as s U bu + b 2 ξ ξu L 1 U ( ξξu 1) =. Define L U := L 1 U ξξ: diffusion operator. Then, with V = U U N s V bv + b 2 ξ ξv L U V = R N.
38 A transport-diffusion equation for U Define, for W L (R + ), ξ L U W := UW U ξ W = so that, if W (ξ) = O(ξ 2 ) near ξ =, L 1 U W = (U ξ ( ξ W ) U 2, U ξ ) W U 2. ξ Remark: L 1 U division by U ξ + ξ2 /2. Then (R) can be written as s U bu + b 2 ξ ξu L 1 U ( ξξu 1) =. Define L U := L 1 U ξξ: diffusion operator. Then, with V = U U N s V bv + b 2 ξ ξv L U V = R N.
39 Energy and dissipation terms V = U U N, s V bv + b 2 ξ ξv L U V = R N. Facts: 1. Estimates are almost linear (up so some commutators...) 2. V = U U N (b s + b 2 )(c 1 ξ 7 + c 2 ξ 8 ) for ξ 1; 3. L U is a diffusion operator (L U 1 U ξξ). Ideas: Differentiate equation/use weights/apply operator L U to make the zero-order + transport term positive: k ξ ( s V bv + b 2 ξ ξv ) ( = s + k 2 b + b 2 2 ξ ξ ) k ξ V. Compromise between control of (b s + b 2 ) 2 by energy/small remainder term/positivity of transport and diffusion... Energy E(s) := (L 2 U V ) ξ 2 H 1 (w) for some weight w.
40 Energy and dissipation terms V = U U N, s V bv + b 2 ξ ξv L U V = R N. Facts: 1. Estimates are almost linear (up so some commutators...) 2. V = U U N (b s + b 2 )(c 1 ξ 7 + c 2 ξ 8 ) for ξ 1; 3. L U is a diffusion operator (L U 1 U ξξ). Ideas: Differentiate equation/use weights/apply operator L U to make the zero-order + transport term positive: k ξ ( s V bv + b 2 ξ ξv ) ( = s + k 2 b + b 2 2 ξ ξ ) k ξ V. Compromise between control of (b s + b 2 ) 2 by energy/small remainder term/positivity of transport and diffusion... Energy E(s) := (L 2 U V ) ξ 2 H 1 (w) for some weight w.
41 Energy and dissipation terms V = U U N, s V bv + b 2 ξ ξv L U V = R N. Facts: 1. Estimates are almost linear (up so some commutators...) 2. V = U U N (b s + b 2 )(c 1 ξ 7 + c 2 ξ 8 ) for ξ 1; 3. L U is a diffusion operator (L U 1 U ξξ). Ideas: Differentiate equation/use weights/apply operator L U to make the zero-order + transport term positive: k ξ ( s V bv + b 2 ξ ξv ) ( = s + k 2 b + b 2 2 ξ ξ ) k ξ V. Compromise between control of (b s + b 2 ) 2 by energy/small remainder term/positivity of transport and diffusion... Energy E(s) := (L 2 U V ) ξ 2 H 1 (w) for some weight w.
42 Tools for the proof Weighted L 2 estimates; Commutator estimates; L estimates coming from maximum principle (sub-super solutions); Bootstrap argument.
43 Conclusion and perspectives Plan Introduction Behaviour near separation: heuristics and formal results Main result and ideas Conclusion and perspectives
44 Conclusion and perspectives Summary Proof of separation for the stationary Prandtl equation in the case of adverse pressure gradient (g(x) = 1); Computation of a self-similar rate compatible with Landau s predictions: Y u Y = x x; Quantitative error estimates between true solution and approximate solution (in weighted H s spaces); Construction of an approximate solution, ODE on the separation rate: relies on arguments close to singularity formation for the nonlinear Schrödinger equation. Energy estimates rely heavily on the structure of the equation, and need to be combined with maximum principle techniques.
45 Conclusion and perspectives Perspectives Other (unstable) separation rates? Better description of the solution in the zone Y (x x) 1/4 ( ξ s 1/4 ); Higher dimensions? What happens after separation? 1. Both turbulent and laminar regimes are possible... But turbulent regimes are out of reach for the time being. 2. The validity of the Prandtl system after separation is far from clear... Thank you for your attention!
On the well-posedness of the Prandtl boundary layer equation
On the well-posedness of the Prandtl boundary layer equation Vlad Vicol Department of Mathematics, The University of Chicago Incompressible Fluids, Turbulence and Mixing In honor of Peter Constantin s
More informationSublayer of Prandtl boundary layers
ublayer of Prandtl boundary layers Emmanuel Grenier Toan T. Nguyen May 12, 2017 Abstract The aim of this paper is to investigate the stability of Prandtl boundary layers in the vanishing viscosity limit:
More informationRecent progress on the vanishing viscosity limit in the presence of a boundary
Recent progress on the vanishing viscosity limit in the presence of a boundary JIM KELLIHER 1 1 University of California Riverside The 7th Pacific RIM Conference on Mathematics Seoul, South Korea 1 July
More informationOn nonlinear instability of Prandtl s boundary layers: the case of Rayleigh s stable shear flows
On nonlinear instability of Prandtl s boundary layers: the case of Rayleigh s stable shear flows Emmanuel Grenier Toan T. Nguyen June 4, 217 Abstract In this paper, we study Prandtl s boundary layer asymptotic
More informationSéminaire Laurent Schwartz
Séminaire Laurent Schwartz EDP et applications Année 2013-2014 David Gérard-Varet and Nader Masmoudi Well-posedness issues for the Prandtl boundary layer equations Séminaire Laurent Schwartz EDP et applications
More informationTopics in Fluid Dynamics: Classical physics and recent mathematics
Topics in Fluid Dynamics: Classical physics and recent mathematics Toan T. Nguyen 1,2 Penn State University Graduate Student Seminar @ PSU Jan 18th, 2018 1 Homepage: http://math.psu.edu/nguyen 2 Math blog:
More informationConstruction of concentrating bubbles for the energy-critical wave equation
Construction of concentrating bubbles for the energy-critical wave equation Jacek Jendrej University of Chicago University of North Carolina February 13th 2017 Jacek Jendrej Energy-critical wave equations
More informationBlow-up on manifolds with symmetry for the nonlinear Schröding
Blow-up on manifolds with symmetry for the nonlinear Schrödinger equation March, 27 2013 Université de Nice Euclidean L 2 -critical theory Consider the one dimensional equation i t u + u = u 4 u, t > 0,
More informationA scaling limit from Euler to Navier-Stokes equations with random perturbation
A scaling limit from Euler to Navier-Stokes equations with random perturbation Franco Flandoli, Scuola Normale Superiore of Pisa Newton Institute, October 208 Newton Institute, October 208 / Subject of
More informationNote on the analysis of Orr-Sommerfeld equations and application to boundary layer stability
Note on the analysis of Orr-Sommerfeld equations and application to boundary layer stability David Gerard-Varet Yasunori Maekawa This note is about the stability of Prandtl boundary layer expansions, in
More informationWorkshop on PDEs in Fluid Dynamics. Department of Mathematics, University of Pittsburgh. November 3-5, Program
Workshop on PDEs in Fluid Dynamics Department of Mathematics, University of Pittsburgh November 3-5, 2017 Program All talks are in Thackerary Hall 704 in the Department of Mathematics, Pittsburgh, PA 15260.
More informationMathematical Hydrodynamics
Mathematical Hydrodynamics Ya G. Sinai 1. Introduction Mathematical hydrodynamics deals basically with Navier-Stokes and Euler systems. In the d-dimensional case and incompressible fluids these are the
More informationBoundary layers for Navier-Stokes equations with slip boundary conditions
Boundary layers for Navier-Stokes equations with slip boundary conditions Matthew Paddick Laboratoire Jacques-Louis Lions Université Pierre et Marie Curie (Paris 6) Séminaire EDP, Université Paris-Est
More informationTable of Contents. Foreword... xiii. Preface... xv
Table of Contents Foreword.... xiii Preface... xv Chapter 1. Fundamental Equations, Dimensionless Numbers... 1 1.1. Fundamental equations... 1 1.1.1. Local equations... 1 1.1.2. Integral conservation equations...
More informationGlobal well-posedness for semi-linear Wave and Schrödinger equations. Slim Ibrahim
Global well-posedness for semi-linear Wave and Schrödinger equations Slim Ibrahim McMaster University, Hamilton ON University of Calgary, April 27th, 2006 1 1 Introduction Nonlinear Wave equation: ( 2
More informationTHE STOKES SYSTEM R.E. SHOWALTER
THE STOKES SYSTEM R.E. SHOWALTER Contents 1. Stokes System 1 Stokes System 2 2. The Weak Solution of the Stokes System 3 3. The Strong Solution 4 4. The Normal Trace 6 5. The Mixed Problem 7 6. The Navier-Stokes
More informationMultiscale Hydrodynamic Phenomena
M2, Fluid mechanics 2014/2015 Friday, December 5th, 2014 Multiscale Hydrodynamic Phenomena Part I. : 90 minutes, NO documents 1. Quick Questions In few words : 1.1 What is dominant balance? 1.2 What is
More informationHamiltonian partial differential equations and Painlevé transcendents
The 6th TIMS-OCAMI-WASEDA Joint International Workshop on Integrable Systems and Mathematical Physics March 22-26, 2014 Hamiltonian partial differential equations and Painlevé transcendents Boris DUBROVIN
More informationOn convergence criteria for incompressible Navier-Stokes equations with Navier boundary conditions and physical slip rates
On convergence criteria for incompressible Navier-Stokes equations with Navier boundary conditions and physical slip rates Yasunori Maekawa Department of Mathematics, Graduate School of Science, Kyoto
More informationMinimal periods of semilinear evolution equations with Lipschitz nonlinearity
Minimal periods of semilinear evolution equations with Lipschitz nonlinearity James C. Robinson a Alejandro Vidal-López b a Mathematics Institute, University of Warwick, Coventry, CV4 7AL, U.K. b Departamento
More informationAPPLICATION OF THE DEFECT FORMULATION TO THE INCOMPRESSIBLE TURBULENT BOUNDARY LAYER
APPLICATION OF THE DEFECT FORMULATION TO THE INCOMPRESSIBLE TURBULENT BOUNDARY LAYER O. ROUZAUD ONERA OAt1 29 avenue de la Division Leclerc - B.P. 72 92322 CHATILLON Cedex - France AND B. AUPOIX AND J.-PH.
More informationFree energy estimates for the two-dimensional Keller-Segel model
Free energy estimates for the two-dimensional Keller-Segel model dolbeaul@ceremade.dauphine.fr CEREMADE CNRS & Université Paris-Dauphine in collaboration with A. Blanchet (CERMICS, ENPC & Ceremade) & B.
More informationAncient solutions to geometric flows
Columbia University Banff May 2014 Outline We will discuss ancient or eternal solutions to geometric flows, that is solutions that exist for all time < t < T where T (, + ]. Such solutions appear as blow
More informationGlobal well-posedness of the primitive equations of oceanic and atmospheric dynamics
Global well-posedness of the primitive equations of oceanic and atmospheric dynamics Jinkai Li Department of Mathematics The Chinese University of Hong Kong Dynamics of Small Scales in Fluids ICERM, Feb
More informationThe Nonlinear Schrodinger Equation
Catherine Sulem Pierre-Louis Sulem The Nonlinear Schrodinger Equation Self-Focusing and Wave Collapse Springer Preface v I Basic Framework 1 1 The Physical Context 3 1.1 Weakly Nonlinear Dispersive Waves
More informationSharp blow-up criteria for the Davey-Stewartson system in R 3
Dynamics of PDE, Vol.8, No., 9-60, 011 Sharp blow-up criteria for the Davey-Stewartson system in R Jian Zhang Shihui Zhu Communicated by Y. Charles Li, received October 7, 010. Abstract. In this paper,
More informationFrom Boltzmann Equations to Gas Dynamics: From DiPerna-Lions to Leray
From Boltzmann Equations to Gas Dynamics: From DiPerna-Lions to Leray C. David Levermore Department of Mathematics and Institute for Physical Science and Technology University of Maryland, College Park
More informationÉquation de Burgers avec particule ponctuelle
Équation de Burgers avec particule ponctuelle Nicolas Seguin Laboratoire J.-L. Lions, UPMC Paris 6, France 7 juin 2010 En collaboration avec B. Andreianov, F. Lagoutière et T. Takahashi Nicolas Seguin
More informationOn Chern-Simons-Schrödinger equations including a vortex point
On Chern-Simons-Schrödinger equations including a vortex point Alessio Pomponio Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari Workshop in Nonlinear PDEs Brussels, September 7
More informationStability of Mach Configuration
Stability of Mach Configuration Suxing CHEN Fudan University sxchen@public8.sta.net.cn We prove the stability of Mach configuration, which occurs in moving shock reflection by obstacle or shock interaction
More informationResearch Article On a Quasi-Neutral Approximation to the Incompressible Euler Equations
Applied Mathematics Volume 2012, Article ID 957185, 8 pages doi:10.1155/2012/957185 Research Article On a Quasi-Neutral Approximation to the Incompressible Euler Equations Jianwei Yang and Zhitao Zhuang
More informationRepresentations of solutions of general nonlinear ODEs in singular regions
Representations of solutions of general nonlinear ODEs in singular regions Rodica D. Costin The Ohio State University O. Costin, RDC: Invent. 2001, Kyoto 2000, [...] 1 Most analytic differential equations
More informationFrequency functions, monotonicity formulas, and the thin obstacle problem
Frequency functions, monotonicity formulas, and the thin obstacle problem IMA - University of Minnesota March 4, 2013 Thank you for the invitation! In this talk we will present an overview of the parabolic
More informationZero Viscosity Limit for Analytic Solutions of the Primitive Equations
Arch. Rational Mech. Anal. 222 (216) 15 45 Digital Object Identifier (DOI) 1.17/s25-16-995-x Zero Viscosity Limit for Analytic Solutions of the Primitive Equations Igor Kukavica, Maria Carmela Lombardo
More informationOn the stability of filament flows and Schrödinger maps
On the stability of filament flows and Schrödinger maps Robert L. Jerrard 1 Didier Smets 2 1 Department of Mathematics University of Toronto 2 Laboratoire Jacques-Louis Lions Université Pierre et Marie
More informationSTABLE STEADY STATES AND SELF-SIMILAR BLOW UP SOLUTIONS
STABLE STEADY STATES AND SELF-SIMILAR BLOW UP SOLUTIONS FOR THE RELATIVISTIC GRAVITATIONAL VLASOV- POISSON SYSTEM Mohammed Lemou CNRS and IRMAR, Rennes Florian Méhats University of Rennes 1 and IRMAR Pierre
More informationGlobal Maxwellians over All Space and Their Relation to Conserved Quantites of Classical Kinetic Equations
Global Maxwellians over All Space and Their Relation to Conserved Quantites of Classical Kinetic Equations C. David Levermore Department of Mathematics and Institute for Physical Science and Technology
More informationBlow-up or No Blow-up? the Role of Convection in 3D Incompressible Navier-Stokes Equations
Blow-up or No Blow-up? the Role of Convection in 3D Incompressible Navier-Stokes Equations Thomas Y. Hou Applied and Comput. Mathematics, Caltech Joint work with Zhen Lei; Congming Li, Ruo Li, and Guo
More informationBoundary-Layer Theory
Hermann Schlichting Klaus Gersten Boundary-Layer Theory With contributions from Egon Krause and Herbert Oertel Jr. Translated by Katherine Mayes 8th Revised and Enlarged Edition With 287 Figures and 22
More informationStability of Feedback Solutions for Infinite Horizon Noncooperative Differential Games
Stability of Feedback Solutions for Infinite Horizon Noncooperative Differential Games Alberto Bressan ) and Khai T. Nguyen ) *) Department of Mathematics, Penn State University **) Department of Mathematics,
More informationHyperbolic Conservation Laws Past and Future
Hyperbolic Conservation Laws Past and Future Barbara Lee Keyfitz Fields Institute and University of Houston bkeyfitz@fields.utoronto.ca Research supported by the US Department of Energy, National Science
More informationA Variational Analysis of a Gauged Nonlinear Schrödinger Equation
A Variational Analysis of a Gauged Nonlinear Schrödinger Equation Alessio Pomponio, joint work with David Ruiz Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari Variational and Topological
More informationEuler equation and Navier-Stokes equation
Euler equation and Navier-Stokes equation WeiHan Hsiao a a Department of Physics, The University of Chicago E-mail: weihanhsiao@uchicago.edu ABSTRACT: This is the note prepared for the Kadanoff center
More informationHomogenization of a Hele-Shaw-type problem in periodic time-dependent med
Homogenization of a Hele-Shaw-type problem in periodic time-dependent media University of Tokyo npozar@ms.u-tokyo.ac.jp KIAS, Seoul, November 30, 2012 Hele-Shaw problem Model of the pressure-driven }{{}
More informationFrom a Mesoscopic to a Macroscopic Description of Fluid-Particle Interaction
From a Mesoscopic to a Macroscopic Description of Fluid-Particle Interaction Carnegie Mellon University Center for Nonlinear Analysis Working Group, October 2016 Outline 1 Physical Framework 2 3 Free Energy
More informationNumerical Methods for the Navier-Stokes equations
Arnold Reusken Numerical Methods for the Navier-Stokes equations January 6, 212 Chair for Numerical Mathematics RWTH Aachen Contents 1 The Navier-Stokes equations.............................................
More information7.6 Example von Kármán s Laminar Boundary Layer Problem
CEE 3310 External Flows (Boundary Layers & Drag, Nov. 11, 2016 157 7.5 Review Non-Circular Pipes Laminar: f = 64/Re DH ± 40% Turbulent: f(re DH, ɛ/d H ) Moody chart for f ± 15% Bernoulli-Based Flow Metering
More informationThe Role of Convection and Nearly Singular Behavior of the 3D Navier-Stokes Equations
The Role of Convection and Nearly Singular Behavior of the 3D Navier-Stokes Equations Thomas Y. Hou Applied and Comput. Mathematics, Caltech PDE Conference in honor of Blake Temple, University of Michigan
More informationBLOWUP THEORY FOR THE CRITICAL NONLINEAR SCHRÖDINGER EQUATIONS REVISITED
BLOWUP THEORY FOR THE CRITICAL NONLINEAR SCHRÖDINGER EQUATIONS REVISITED TAOUFIK HMIDI AND SAHBI KERAANI Abstract. In this note we prove a refined version of compactness lemma adapted to the blowup analysis
More informationWaves in a Shock Tube
Waves in a Shock Tube Ivan Christov c February 5, 005 Abstract. This paper discusses linear-wave solutions and simple-wave solutions to the Navier Stokes equations for an inviscid and compressible fluid
More informationHamiltonian partial differential equations and Painlevé transcendents
Winter School on PDEs St Etienne de Tinée February 2-6, 2015 Hamiltonian partial differential equations and Painlevé transcendents Boris DUBROVIN SISSA, Trieste Lecture 2 Recall: the main goal is to compare
More informationNumerical Study of Oscillatory Regimes in the KP equation
Numerical Study of Oscillatory Regimes in the KP equation C. Klein, MPI for Mathematics in the Sciences, Leipzig, with C. Sparber, P. Markowich, Vienna, math-ph/"#"$"%& C. Sparber (generalized KP), personal-homepages.mis.mpg.de/klein/
More informationNonuniqueness of weak solutions to the Navier-Stokes equation
Nonuniqueness of weak solutions to the Navier-Stokes equation Tristan Buckmaster (joint work with Vlad Vicol) Princeton University November 29, 2017 Tristan Buckmaster (Princeton University) Nonuniqueness
More informationGevrey spaces and nonlinear inviscid damping for 2D Euler.
Gevrey spaces and nonlinear inviscid damping for 2D Euler. Nader Masmoudi (CIMS) joint work with Jacob Bedrossian (CIMS) October 18, 2013 MSRI, October 2013 First part is joint with Tak Kwong Wong (UPenn)
More informationNONLOCAL DIFFUSION EQUATIONS
NONLOCAL DIFFUSION EQUATIONS JULIO D. ROSSI (ALICANTE, SPAIN AND BUENOS AIRES, ARGENTINA) jrossi@dm.uba.ar http://mate.dm.uba.ar/ jrossi 2011 Non-local diffusion. The function J. Let J : R N R, nonnegative,
More informationBoundary layer flows The logarithmic law of the wall Mixing length model for turbulent viscosity
Boundary layer flows The logarithmic law of the wall Mixing length model for turbulent viscosity Tobias Knopp D 23. November 28 Reynolds averaged Navier-Stokes equations Consider the RANS equations with
More informationThe enigma of the equations of fluid motion: A survey of existence and regularity results
The enigma of the equations of fluid motion: A survey of existence and regularity results RTG summer school: Analysis, PDEs and Mathematical Physics The University of Texas at Austin Lecture 1 1 The review
More informationExamples of Boundary Layers Associated with the Incompressible Navier-Stokes Equations
Examples of Boundary Layers Associated with the Incompressible Navier-Stokes Equations Xiaoming Wang Department of Mathematics, Florida State University, Tallahassee, FL 32306 June 24, 2010 Dedicated to
More informationExamples of Boundary Layers Associated with the Incompressible Navier-Stokes Equations
Chin. Ann. Math.??B(?), 2010, 1 20 DOI: 10.1007/s11401-007-0001-x Chinese Annals of Mathematics, Series B c The Editorial Office of CAM and Springer-Verlag Berlin Heidelberg 2010 Examples of Boundary Layers
More informationTurbulence Modeling I!
Outline! Turbulence Modeling I! Grétar Tryggvason! Spring 2010! Why turbulence modeling! Reynolds Averaged Numerical Simulations! Zero and One equation models! Two equations models! Model predictions!
More informationRecent result on porous medium equations with nonlocal pressure
Recent result on porous medium equations with nonlocal pressure Diana Stan Basque Center of Applied Mathematics joint work with Félix del Teso and Juan Luis Vázquez November 2016 4 th workshop on Fractional
More informationNumerical schemes for short wave long wave interaction equations
Numerical schemes for short wave long wave interaction equations Paulo Amorim Mário Figueira CMAF - Université de Lisbonne LJLL - Séminaire Fluides Compréssibles, 29 novembre 21 Paulo Amorim (CMAF - U.
More information5.8 Laminar Boundary Layers
2.2 Marine Hydrodynamics, Fall 218 ecture 19 Copyright c 218 MIT - Department of Mechanical Engineering, All rights reserved. 2.2 - Marine Hydrodynamics ecture 19 5.8 aminar Boundary ayers δ y U potential
More informationRegularity and Decay Estimates of the Navier-Stokes Equations
Regularity and Decay Estimates of the Navier-Stokes Equations Hantaek Bae Ulsan National Institute of Science and Technology (UNIST), Korea Recent Advances in Hydrodynamics, 216.6.9 Joint work with Eitan
More informationEnergy dissipation caused by boundary layer instability at vanishing viscosity
Energy dissipation caused by boundary layer instability at vanishing viscosity Marie Farge, Ecole Normale Supérieure, Paris Kai Schneider, Université d Aix-Marseille in collaboration with Romain Nguyen-Nouch
More informationof some mathematical models in physics
Regularity, singularity and well-posedness of some mathematical models in physics Saleh Tanveer (The Ohio State University) Background Mathematical models involves simplifying assumptions where "small"
More informationDynamics of energy-critical wave equation
Dynamics of energy-critical wave equation Carlos Kenig Thomas Duyckaerts Franke Merle September 21th, 2014 Duyckaerts Kenig Merle Critical wave 2014 1 / 22 Plan 1 Introduction Duyckaerts Kenig Merle Critical
More informationBielefeld Course on Nonlinear Waves - June 29, Department of Mathematics University of North Carolina, Chapel Hill. Solitons on Manifolds
Joint work (on various projects) with Pierre Albin (UIUC), Hans Christianson (UNC), Jason Metcalfe (UNC), Michael Taylor (UNC), Laurent Thomann (Nantes) Department of Mathematics University of North Carolina,
More informationProblem 3. Give an example of a sequence of continuous functions on a compact domain converging pointwise but not uniformly to a continuous function
Problem 3. Give an example of a sequence of continuous functions on a compact domain converging pointwise but not uniformly to a continuous function Solution. If we does not need the pointwise limit of
More informationIntroduction to Partial Differential Equations
Introduction to Partial Differential Equations Partial differential equations arise in a number of physical problems, such as fluid flow, heat transfer, solid mechanics and biological processes. These
More informationOn the inviscid limit of the Navier-Stokes equations
On the inviscid limit of the Navier-Stokes equations Peter Constantin, Igor Kukavica, and Vlad Vicol ABSTRACT. We consider the convergence in the L norm, uniformly in time, of the Navier-Stokes equations
More informationArchimedes Center for Modeling, Analysis & Computation. Singular solutions in elastodynamics
Archimedes Center for Modeling, Analysis & Computation Singular solutions in elastodynamics Jan Giesselmann joint work with A. Tzavaras (University of Crete and FORTH) Supported by the ACMAC project -
More informationSingular limits for reaction-diffusion equations with fractional Laplacian and local or nonlocal nonlinearity
Singular limits for reaction-diffusion equations with fractional Laplacian and local or nonlocal nonlinearity Sylvie Méléard, Sepideh Mirrahimi September 2, 214 Abstract We perform an asymptotic analysis
More informationFluid Approximations from the Boltzmann Equation for Domains with Boundary
Fluid Approximations from the Boltzmann Equation for Domains with Boundary C. David Levermore Department of Mathematics and Institute for Physical Science and Technology University of Maryland, College
More informationChapter 3 Second Order Linear Equations
Partial Differential Equations (Math 3303) A Ë@ Õæ Aë áöß @. X. @ 2015-2014 ú GA JË@ É Ë@ Chapter 3 Second Order Linear Equations Second-order partial differential equations for an known function u(x,
More informationLocal smoothing and Strichartz estimates for manifolds with degenerate hyperbolic trapping
Local smoothing and Strichartz estimates for manifolds with degenerate hyperbolic trapping H. Christianson partly joint work with J. Wunsch (Northwestern) Department of Mathematics University of North
More informationASYMPTOTIC STRUCTURE FOR SOLUTIONS OF THE NAVIER STOKES EQUATIONS. Tian Ma. Shouhong Wang
DISCRETE AND CONTINUOUS Website: http://aimsciences.org DYNAMICAL SYSTEMS Volume 11, Number 1, July 004 pp. 189 04 ASYMPTOTIC STRUCTURE FOR SOLUTIONS OF THE NAVIER STOKES EQUATIONS Tian Ma Department of
More informationGrowth of Sobolev norms for the cubic NLS
Growth of Sobolev norms for the cubic NLS Benoit Pausader N. Tzvetkov. Brown U. Spectral theory and mathematical physics, Cergy, June 2016 Introduction We consider the cubic nonlinear Schrödinger equation
More informationOn some nonlinear parabolic equation involving variable exponents
On some nonlinear parabolic equation involving variable exponents Goro Akagi (Kobe University, Japan) Based on a joint work with Giulio Schimperna (Pavia Univ., Italy) Workshop DIMO-2013 Diffuse Interface
More informationUniversité de Cergy-Pontoise. Insitut Universitaire de France. joint work with Frank Merle. Hatem Zaag. wave equation
The blow-up rate for the critical semilinear wave equation Hatem Zaag CNRS École Normale Supérieure joint work with Frank Merle Insitut Universitaire de France Université de Cergy-Pontoise utt = u + u
More informationSimulating Drag Crisis for a Sphere Using Skin Friction Boundary Conditions
Simulating Drag Crisis for a Sphere Using Skin Friction Boundary Conditions Johan Hoffman May 14, 2006 Abstract In this paper we use a General Galerkin (G2) method to simulate drag crisis for a sphere,
More informationMarching on the BL equations
Marching on the BL equations Harvey S. H. Lam February 10, 2004 Abstract The assumption is that you are competent in Matlab or Mathematica. White s 4-7 starting on page 275 shows us that all generic boundary
More informationIgor Cialenco. Department of Applied Mathematics Illinois Institute of Technology, USA joint with N.
Parameter Estimation for Stochastic Navier-Stokes Equations Igor Cialenco Department of Applied Mathematics Illinois Institute of Technology, USA igor@math.iit.edu joint with N. Glatt-Holtz (IU) Asymptotical
More informationAA214B: NUMERICAL METHODS FOR COMPRESSIBLE FLOWS
AA214B: NUMERICAL METHODS FOR COMPRESSIBLE FLOWS 1 / 43 AA214B: NUMERICAL METHODS FOR COMPRESSIBLE FLOWS Treatment of Boundary Conditions These slides are partially based on the recommended textbook: Culbert
More informationGlobal well-posedness for the critical 2D dissipative quasi-geostrophic equation
Invent. math. 167, 445 453 (7) DOI: 1.17/s-6--3 Global well-posedness for the critical D dissipative quasi-geostrophic equation A. Kiselev 1, F. Nazarov, A. Volberg 1 Department of Mathematics, University
More informationOn universality of critical behaviour in Hamiltonian PDEs
Riemann - Hilbert Problems, Integrability and Asymptotics Trieste, September 23, 2005 On universality of critical behaviour in Hamiltonian PDEs Boris DUBROVIN SISSA (Trieste) 1 Main subject: Hamiltonian
More informationIntegro-differential equations: Regularity theory and Pohozaev identities
Integro-differential equations: Regularity theory and Pohozaev identities Xavier Ros Oton Departament Matemàtica Aplicada I, Universitat Politècnica de Catalunya PhD Thesis Advisor: Xavier Cabré Xavier
More informationPartial differential equation for temperature u(x, t) in a heat conducting insulated rod along the x-axis is given by the Heat equation:
Chapter 7 Heat Equation Partial differential equation for temperature u(x, t) in a heat conducting insulated rod along the x-axis is given by the Heat equation: u t = ku x x, x, t > (7.1) Here k is a constant
More informationSEMILINEAR ELLIPTIC EQUATIONS WITH DEPENDENCE ON THE GRADIENT
Electronic Journal of Differential Equations, Vol. 2012 (2012), No. 139, pp. 1 9. ISSN: 1072-6691. URL: http://ejde.math.txstate.edu or http://ejde.math.unt.edu ftp ejde.math.txstate.edu SEMILINEAR ELLIPTIC
More informationDISPERSIVE EQUATIONS: A SURVEY
DISPERSIVE EQUATIONS: A SURVEY GIGLIOLA STAFFILANI 1. Introduction These notes were written as a guideline for a short talk; hence, the references and the statements of the theorems are often not given
More information1. Introduction, tensors, kinematics
1. Introduction, tensors, kinematics Content: Introduction to fluids, Cartesian tensors, vector algebra using tensor notation, operators in tensor form, Eulerian and Lagrangian description of scalar and
More informationρ Du i Dt = p x i together with the continuity equation = 0, x i
1 DIMENSIONAL ANALYSIS AND SCALING Observation 1: Consider the flow past a sphere: U a y x ρ, µ Figure 1: Flow past a sphere. Far away from the sphere of radius a, the fluid has a uniform velocity, u =
More informationObstacle problems for nonlocal operators
Obstacle problems for nonlocal operators Camelia Pop School of Mathematics, University of Minnesota Fractional PDEs: Theory, Algorithms and Applications ICERM June 19, 2018 Outline Motivation Optimal regularity
More informationWeek 6 Notes, Math 865, Tanveer
Week 6 Notes, Math 865, Tanveer. Energy Methods for Euler and Navier-Stokes Equation We will consider this week basic energy estimates. These are estimates on the L 2 spatial norms of the solution u(x,
More informationPDEs, part 1: Introduction and elliptic PDEs
PDEs, part 1: Introduction and elliptic PDEs Anna-Karin Tornberg Mathematical Models, Analysis and Simulation Fall semester, 2013 Partial di erential equations The solution depends on several variables,
More information4.2 Concepts of the Boundary Layer Theory
Advanced Heat by Amir Faghri, Yuwen Zhang, and John R. Howell 4.2 Concepts of the Boundary Layer Theory It is difficult to solve the complete viscous flow fluid around a body unless the geometry is very
More informationUNIT IV BOUNDARY LAYER AND FLOW THROUGH PIPES Definition of boundary layer Thickness and classification Displacement and momentum thickness Development of laminar and turbulent flows in circular pipes
More informationAsymptotic behavior of infinity harmonic functions near an isolated singularity
Asymptotic behavior of infinity harmonic functions near an isolated singularity Ovidiu Savin, Changyou Wang, Yifeng Yu Abstract In this paper, we prove if n 2 x 0 is an isolated singularity of a nonegative
More informationFinite-time singularity formation for Euler vortex sheet
Finite-time singularity formation for Euler vortex sheet Daniel Coutand Maxwell Institute Heriot-Watt University Oxbridge PDE conference, 20-21 March 2017 Free surface Euler equations Picture n N x Ω Γ=
More informationRegularization by noise in infinite dimensions
Regularization by noise in infinite dimensions Franco Flandoli, University of Pisa King s College 2017 Franco Flandoli, University of Pisa () Regularization by noise King s College 2017 1 / 33 Plan of
More information